Here is my take on a 13-district Michigan:
https://davesredistricting.org/join/cf3b2fa2-7fcd-4b0d-adeb-6347e4ef6b63Tries to preserve COIs, but the breakdown is as follows:
MI-01: Northern Michigan, Trump +21, Safe R
MI-02: Muskegon and the remnant of current MI-04, Trump +18, Safe R
MI-03: Grand Rapids, Ionia/Barry/Montcalm, Trump +9, Lean R
MI-04: Lansing, Saginaw, and rural areas in between, Clinton +5, Lean D
MI-05: Flint, Livingston, Western Oakland, Trump +9, Tossup
MI-06: Kalamazoo, SW Michigan, inland Ottawa County, Trump +14, Likely R
MI-07: Monroe County, Indiana border, Trump +23, Safe R
MI-08: Pontiac, Troy, West Bloomfield, southern Oakland, Clinton +12, Likely D
MI-09: southern Macomb County, Trump +9, Tossup
MI-10: northern Macomb, NE Oakland, the Thumb, and Bay City, Trump +29, Safe R
MI-11: Washtenaw and western Wayne, Clinton +21, Safe D
MI-12: Wyandotte, Romulus, central Wayne County, 45.6% black, Clinton +46, Safe D
MI-13: downtown Detroit, 56.3% black, Clinton +67, Safe D
Overall, I think this map has an ample amount of competitive districts. Districts 1, 2, 3, 6, 7, and 10 should likely go to the GOP. Districts 4, 5, and 9 are competitive but should be winnable for the right Dem (Levin, Kildee, the Macomb executive, etc). Districts 8, 11, 12, and 13 are all solid D holds. Overall, this leads to a 4D-3C-6R spread, which would roughly average out to 6D-7R or 7D-6R. Trends as well will make the 4/5/9 combo, as well as MI-3 and to a lesser extent MI-6 competitive.
